Methods for improving syngas-to-alcohol catalyst activity and selectivity
The invention herein provides methods of activating a catalyst composition. These methods include annealing a catalyst with an inert gas, under effective conditions, and then contacting the annealed catalyst with syngas to produce an activated catalyst. These steps can also be reversed. The activated catalysts can be employed to convert syngas into products, such as alcohols, with improved selectivities and yields.
1. A method of activating a catalyst, said method comprising:
(a) annealing said catalyst with a first gas phase comprising an inert gas, under effective conditions including a first temperature of less than about 450° C. and a first pressure of less than about 200 atm, thereby producing an annealed catalyst; and
(b) contacting said annealed catalyst with a second gas phase comprising syngas, under conditions comprising a second temperature of from about 150° C. to about 350° C. and a second pressure of from about 30 atm to about 200 atm, thereby producing an activated catalyst.
2. The method of claim 1 , wherein said inert gas is selected from the group consisting of N 2 , He, Ne, Ar, Kr, Xe, Rn, and combinations thereof.
3. The method of claim 2 , wherein said inert gas is He.
4. The method of claim 1 , wherein said annealing step comprises contacting said catalyst with H 2 , CO, or a mixture of H 2 and CO.
5. The method of claim 1 , wherein said second gas phase further comprises methane and/or carbon dioxide.
6. The method of claim 1 , wherein said first temperature is selected from about 280° C. to about 350° C.
7. The method of claim 1 , wherein said first pressure is selected from about 80 atm to about 120 atm.
8. The method of claim 1 , wherein said activated catalyst comprises cobalt, molybdenum, sulfur, and potassium.
9. The method of claim 1 , wherein said second temperature is selected from about 250° C. to about 325° C.
10. The method of claim 1 , wherein said second pressure is selected from about 80 atm to about 120 atm.
11. The method of claim 1 , wherein step (a) is conducted for at least five hours.
12. The method of claim 1 , further comprising (c) converting syngas to at least one C 1 -C 4 alcohol over said activated catalyst.
13. The method of claim 1 , wherein steps (a) and (b) are conducted in the same vessel.
14. The method of claim 12 , wherein at least two of steps (a), (b), and (c) are conducted in the same vessel.
15. The method of claim 1 , said method comprising a plurality of increasing temperatures between said first and second temperatures, and further comprising a plurality of increasing pressures between said first and second pressures.
16. The method of claim 1 , wherein said first temperature and said second temperature are about the same.
17. The method of claim 1 , wherein said first pressure and said second pressure are about the same.
18. The method of claim 12 , wherein said converting is conducted at a temperature that is about the same as said first temperature, and is further conducted at a pressure that is about the same as said first pressure.
19. The method of claim 12 , wherein said converting is conducted at a temperature that is about the same as said second temperature, and is further conducted at a pressure that is about the same as said second pressure.
20. The method of claim 12 , wherein said at least one C 1 -C 4 alcohol includes ethanol.
21. The method of claim 20 , wherein the selectivity of ethanol produced by said activated catalyst is higher than the selectivity of ethanol that would have been produced in the absence of step (a).
22. The method of claim 20 , wherein the yield of ethanol produced by said activated catalyst is higher than the yield of ethanol that would have been produced in the absence of step (a).
23. The method of claim 20 , wherein the selectivity of CO 2 produced by said activated catalyst is lower than the selectivity of CO 2 that would have been produced in the absence of step (a).
24. A method of activating a catalyst, said method comprising:
(a) contacting said catalyst with a first gas phase comprising syngas, under conditions comprising a first temperature of less than about 450° C. and a first pressure of less than about 200 atm, thereby producing a pre-activated catalyst; and
(b) annealing said pre-activated catalyst with a second gas phase consisting essentially of an inert gas, under effective conditions comprising a second temperature of from about 150° C. to about 350° C. and a second pressure of from about 30 atm to about 200 atm, thereby producing an activated catalyst.
25. A method of activating a Co/Mo/S/K catalyst, said method comprising:
(a) annealing said catalyst with helium at a temperature of about 310° C. and a pressure of about 1270 psi, thereby producing an annealed catalyst; and
(b) contacting said annealed catalyst with syngas at a temperature of about 280° C. and a pressure of about 1270 psi, thereby producing an activated Co/Mo/S/K catalyst.
26. A method of producing an annealed catalyst intermediate, said method comprising:
(a) providing an effective starting catalyst composition; and
(b) annealing said starting catalyst composition with a first gas phase comprising an inert gas, under conditions including a temperature of less than about 450° C., thereby producing an annealed catalyst intermediate.
27. The method of claim 26 wherein said inert gas is selected from the group consisting of N 2 , He, Ne, Ar, Kr, Xe, Rn, and combinations thereof.
28. The method of claim 27 , wherein said inert gas is He.
29. The method of claim 26 , wherein said annealing step comprises contacting said catalyst with H 2 , CO, or a mixture of H 2 and CO.
30. The method of claim 29 , wherein said annealing step further comprises contacting said catalyst with methane and/or carbon dioxide.
31. The method of claim 26 , wherein said temperature is selected from about 280° C. to about 350° C.
32. The method of claim 26 , wherein said effective conditions include a pressure of less than about 200 atm.
33. The method of claim 32 , wherein said pressure is selected from about 80 atm to about 120 atm.
34. The method of claim 26 , wherein said annealed catalyst intermediate comprises cobalt, molybdenum, sulfur, and potassium.
35. The method of claim 26 , wherein step (b) is conducted for at least five hours.
36. The method of claim 26 , further comprising converting syngas to at least one C 1 -C 4 alcohol over a catalyst generated from said annealed catalyst intermediate.
37. The method of claim 36 , wherein said at least one C 1 -C 4 alcohol includes ethanol.
38. The method of claim 37 , wherein the selectivity of ethanol produced by said catalyst is higher than the selectivity of ethanol that would have been produced in the absence of step (b).
39. The method of claim 37 , wherein the yield of ethanol produced by said activated catalyst is higher than the yield of ethanol that would have been produced in the absence of step (b).